In the field of cable manufacturing, a cable core includes elements to transmit optical and/or electrical signals that may be optical waveguides or electrical wires. The optical waveguides may be grouped together and surrounded by a sheath of polymer material to form a buffer tube. For instance, one or more buffer tubes may be grouped together within a cable core. The cable core is surrounded by a cable jacket that may be made of polymer material. In order to manufacture, in a first step, the sheath of the buffer tube around the optical fibers and, in a second step, the jacket around the cable core, a process of providing a melt polymer material and disposing the polymer material at an elevated temperature around the optical fibers and the cable core, respectively, in a crosshead is a commonly used method. In general, extruding polymer materials over elongate members may be used in other technical fields as well.
In particular with optical fiber cable technology, the optical fibers are sensitive to thermal and/or mechanical stress so that the manufacturing process must be performed under controlled conditions to meet sensitivity requirements. In particular, the optical performance may suffer from excess process temperature.